Volume Three - The Pontoon Era - The plant specification, pumping plan and operation of the pontoon . . .

The specification for the pumps stated “The lubrication throughout to be of the most perfect kind so that all parts can be oiled whilst the Engine is in motion.”

The images and descriptions are based upon the articles from “The Engineer” of 1902 and 1904 and correspondence between Gwynnes Limited and the Wallsend yard obtained from the Newcastle Archives.

The engineers at Penarth also had an input to the specification but seem to have been guided strongly, or bullied, by the recommendations and experience of the builders of the many pontoons already in service. Clark & Standfield were the World's premier designers of floating docks and by 1912, Swan, Hunter and Wigham Richardson led the way in their construction.

Centrifugal pumps

	The centrifugal pumps pumped water from the pontoon to provide the lifting power of the pontoon. At Penarth, the specification was amended in consultation with the Penarth engineers to provide an 18” diameter discharge with a 19” diameter suction. The pump impeller, or "discs", as they were termed at the time, were 3 feet in diameter. The specification stated:-

“The pump to be of Centrifugal type, casing of cast iron of volute form, all of proper proportions having moveable top cover enabling the disc to be removed; provided with long stuffing box and bearing. The suction to be of the single inlet type so that the pump can stand on the main drain at bottom of Dock. The disc to be of cast steel of proper proportions of the shrouded type carefully attached to spindle by cone and nut. The pump spindle to be of best mild steel having solid forged coupling at upper end.”

I have not been able to establish (yet) the manufacturer (but most probably Gwynnes, Invincible pumping plant) or specification of the centrifugal pumps so the image is of those used for the Kobe installation and is representative of the type of pump used in that period at Penarth.